Effects of Clostridium sporogenes on Myeloid-Derived Suppressor Cells and Inflammatory Factors in Mice with Graves' Disease

Objective This study was designed to analyze the effects of Clostridium sporogenes (C. sporogenes) on myeloid-derived suppressor cells (MDSCs) and inflammatory factors in mice with Graves disease (GD).Methods A GD mice model was constructed using recombinant adenovirus overexpressing Ad-hTSHR-289 in 6-week-old female BALB/C mice. After modeling, the mice were randomly divided into 6 groups (8 mice/group): blank control group (CON), C. sporogenes intervention negative control group (CON_C.sp), C. sporogenes supernatant intervention negative control group (CON_C.sp_supernate), GD model group (MOD), C. sporogenes intervention GD model group (MOD_C.sp) and C. sporogenes supernatant intervention GD model group (MOD_ C.sp_supernate), and gave normal saline (NS). C. sporogenes or C. sporogenes supernatant was gavaged intervention for 6 weeks, the proportions of MDSCs and their subtype monocyte-like myeloid-derived suppressor cells M-MDSCs in spleen were respectively detected by flow cytometry. The expression levels of tumor necrosis factor -α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), free thyroxine (FT4), thyroid-stimulating hormone receptor antibody (TRAb) and thyroid-stimulating hormone (TSH) in plasma were determined by ELISA. Pearson method was used to analyze the correlation among MDSCs, M-MDSCs, inflammatory cytokines and thyroxine.Results Compared with the model group mice, the proportion of M-MDSCs in GD model group (MOD_C.sp_supernate) treated with C. sporogenes supernatant was increased in spleen. The plasma TNF-α and IL-6 of the GD model group (MOD_C.sp and MOD_C.sp_supernate) treated with C. sporogenes and their supernatant were decreased, and IL-10 was increased. Analysis of the correlation between Spleen MDSCs, M-MDSCs and plasma inflammatory cytokines showed that spleen MDSCs and M-MDSCs were negatively correlated with plasma TNF-α and IL-6, but positively correlated with IL-10. Spleen MDSCs and M-MDSCs were negatively correlated with plasma FT4 and TRAb, but positively correlated with TSH.Conclusion C. sporogenes can increase the proportion of M-MDSCs in the spleen of GD mice, and improve GD inflammatory response in mice.